Multi-light fiber source for fiber end-surface inspection

ABSTRACT

A fiber end-surface inspection device and method illuminates the fiber end-surface from at least 2 different illumination angles, taking observations at the different angles, for detection of fiber end-surface imperfections, scratches or the like.

BACKGROUND

This disclosure relates to testing of fiber optic communication lines,and more particularly to the inspection of the end surfaces of fiberoptic cables.

Current fiber inspection probes (or cameras) in the market use one fixedlight (for example, a LED or light bulb) that shines light through aprism onto the fiber end-surface for inspection. The detection ofdefects on fiber end-surface can be dependent on the angle of the singlelight source provided with a typical fiber inspection tool. With atypical single light source tool, in a particular case it may be that ascratch cannot be detected from first inspection, but, upon a usermanually rotating or otherwise maneuvering the fiber to get differentangles of light falling on the fiber end, scratches that might not bevisible at first, may come into view.

To inspect dirt or chirp of fiber connector-end, a small fiber scope (orprobe) is typically used. In machine vision systems, light source is oneof the key factors. Some of the big scope stations use fiber ring lightsources and other small scopes use a LED light next to the scope. If thelight shades from center or perimeter like fiber ring light source, someof the defects (dirt, chirp, or scratch) are difficult to find becausedefects can be obscured by shadows. On the other hand, if the light isfrom side, the other half of the fiber-end becomes dark because thefiber-end is not a straight plane but instead has curvature. Thus, someexperienced technicians rotate the fiber to inspect the other side ofthe fiber end. However, this method does not work with angled connectorsand with automated fiber-end inspection system using machine vision.Also, requiring such manual movement to accomplish testing adds a factorof operator skill to the reliability of the test results, which isundesirable.

SUMMARY

In accordance with the disclosure, a fiber end-surface inspection toolprovides dual (or multiple) light sources for inspection, and can togglethe application of light from the different sources, providing improvedscratch detection.

Accordingly, it is an advantage of the present disclosure to provide animproved fiber end-surface inspection tool.

It is a further advantage of the present disclosure to provide animproved method for inspecting fiber optic communication line fiberend-surfaces.

It is yet another advantage of the present disclosure to provide animproved system for inspecting the end-surfaces of fiber optic cables.

The subject matter of the present technology is particularly pointed outand distinctly claimed in the concluding portion of this specification.However, both the organization and method of operation, together withfurther advantages and embodiments thereof, may best be understood byreference to the following description taken in connection withaccompanying drawings wherein like reference characters refer to likeelements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a device in accordance with the presentdisclosure; and

FIG. 2 is a flow chart of the operational steps of performing tests withthe device of FIG. 1;

FIG. 3 is a view of an implementation of the light sources and camera;

FIG. 4 is a view of an alternative implementation of the light sourceand camera, using a variable angle mirror;

FIG. 5 is a view of the system of FIG. 4 with the mirror at a firstangle;

FIG. 6 is a view of the system of FIG. 4 with the mirror at a secondangle; and

FIG. 7 is a flowchart of the operational steps with a pivoting mirrorconfiguration.

DETAILED DESCRIPTION

The system according to a preferred embodiment of the present disclosurecomprises a device that uses two (or more) LEDs positioned at locationsto provide different angles of application of the light source. Inoperation, first, one LED is turned on, and an image of the fiberend-surface is taken. Then, that first LED is turned off and the secondLED is turned on, and another image is taken, providing multiple anglesof applied light automatically, without requiring the operator tomanually rotate, or maneuver the fiber or the light source.

Referring to FIG. 1 a block diagram of a test device 10 in accordancewith the disclosure, the device includes a test chamber 12 (which maycomprise an open air space), having first and second light sources 14,16, suitably LEDs in a particular embodiment, with the 2 LEDs positionedat alternated sides of a camera 18. The camera and LEDs are controlledby/communicate with a processor 20. Camera 18 observes viewing position22 which is positioned at or receives therein a fiber optic cable end 24therein, for inspection.

A display 26 for displaying results, images and providing a controlinterface (in conjunction with user interface 28 (e.g., keys or touchscreen functionality) also interfaces with the processor. Power supply30, which can be battery or AC mains supply, provides power to operatethe device.

Referring now to FIG. 2, a flow chart of the operational steps oftesting a fiber end-surface, first, the fiber is positioned (step 32) atan inspection site (for example, viewing position 22), whereupon thefirst light (assuming a 2 light system) is turned on (step 34) and animage of the fiber end-surface is captured (step 36), and provided tothe processor or otherwise stored. Next, the first light is turned off(step 38) and the second light is turned on (step 40), providingillumination of the fiber surface from a different light angle. An imageis captured (step 42) and stored or otherwise held for further use, andthe second light is turned off (step 44). The resulting images may besuperimposed (step 45), employing the images taken in differentdirections to get a complete image that contains defects observed inevery directions. The resulting combined image, that contains all thedefects as observed from the multiple angles of illumination, may beprocessed (step 47) by image processing algorithm to detect defectsautomatically.

The resulting images may be displayed also for visual inspection by anoperator of the device, thereby providing detection of defects,scratches, etc.

The operation may be automated by processor 20, in conjunction with thecamera to automatically detect when a fiber is present, or can beperformed under direction of a user.

FIG. 3 is an illustration of a two light source illumination systemwherein camera 18′ observes the fiber under test 24′ through first andsecond coated prisms which are positioned in line with one another, withtheir reflection direction oriented towards the fiber under test. Firstprism 46 is closest to camera 18′, and receives and reflects light fromlight source 50 at orientation 52. Second prism 48 is spaced between thefirst prism and the fiber under test, with its reflective surfacedirected to reflect towards the fiber under test. Light source 54 ispositioned to provide light to the prism 48, which is reflected towardsthe fiber under test at orientation 56. The prisms are positioned suchthat orientations 52 and 56 provide light to the fiber under test atdifferent angles. As is known in the art, the prisms reflect part(typically half) of light from the light sources, and part of the lightreflected from the surface of the fiber under test is transmitted tocamera 18′ which observes the reflected light 58 from the fiber undertest as passed through the prisms. The illumination of lights sources50, 54 may be accomplished in accordance with the steps of FIG. 2,wherein the light sources are alternately illuminated.

FIG. 4 illustrates an alternate embodiment employing a single lightsource and an alternating angled mirror to provide different angles oflight injection to the fiber under test. Partial mirror 60 is positionedbetween camera 18′ and fiber under test 24′, with the mirror adapted tobe pivoted about axis 62 as illustrated by arc 64. Two possiblepositions of the mirror are illustrated in FIG. 4, a left-most andright-most position (when considered from the top of the mirror in FIG.4) Light source 66 shines light 68 to the reflective surface of themirror, causing reflected light 70, 72 to be transmitted to the fiberunder test, reflected light 72 coming from the mirror when in theright-most tilt position and reflected light 70 coming from the mirrorwhen in the left-most tilt position. Camera 18′ then observes thereflected light from the fiber under test.

FIG. 5 is representative of the setup with the mirror in a first,left-most position, and illustrates the transmission 70 and reflection74′ of light with the mirror at a first angle, while FIG. 6 illustratesthe transmission, and reflection of light with the mirror at a secondangle. The fiber under test is thus illustrated with light from twodifferent angles. Configurations may be employed that alter the mirrorangle to more than 2 different angles.

FIG. 7 is a flowchart of the operational steps with a pivoting mirrorconfiguration, wherein the fiber is positioned for inspection at step32′, the light source 66 is illuminated and the mirror 60 is moved to afirst position, step 76. An image is then captured at step 78 andsuitably stored for future use and processing. Next, a decision is madeas to whether sufficient images have been captured. Ideally 2 or moredifferent mirror position images would be taken. If a sufficient numberhave not been taken, then in block 82 is entered to reposition themirror to a different angle then previously employed, and the processloops back to block 78 to capture another image. If a sufficient ordesired number of images have been captured at block 80, then the lightsource is turned off at step 84, the images taken and stored may besuperimposed (step 85) to provide a single image having all the defectsas detected from various angles of illumination, and analysis may beperformed on the combined image (step 87) and the process is complete.

An alternative embodiment employs multiple light sources, for examplemore than 2 total, with the light sources positioned spatially indifferent locations to provide additional angles of light illuminationof the fiber under test, or, as noted above, by angling of mirror 60 tomore than 2 different angles relative to the fiber under test.

Still further, a single light source may be employed, with direction ofthe light through a splitter or other method so as to provideillumination of the fiber end-surface from more than one angle.

The test device may be implemented as a hand held/portable device, or abench top test unit, for example.

Accordingly, an improved method and device for inspecting fiberend-surfaces is provided.

While a preferred embodiment of the technology has been shown anddescribed, it will be apparent to those skilled in the art that manychanges and modifications may be made without departing from the broaderaspects. The appended claims are therefore intended to cover all suchchanges and modifications as fall within the true spirit and scope ofthe technology.

1. A fiber end-surface detection device, comprising: a first lightsource positioned to illuminate the fiber end-surface from a firstillumination angle; a second light source positioned to illuminate thefiber end-surface from a second illumination angle; and a vision devicefor observing the fiber end-surface under illumination from the firstlight source and under illumination from the second light source,wherein said first and second light sources are located on oppositesides with respect to the vision device position.
 2. The fiberend-surface detection device according to claim 1, wherein said firstand second light sources comprise LEDs.
 3. (canceled)
 4. The fiberend-surface detection device according to claim 1, further comprisingfirst and second prisms adapted to reflect light from said first andsecond light sources toward the fiber end-surface, and to pass reflectedlight from the fiber end-surface to the vision device.
 5. The fiberend-surface detection device according to claim 1, further comprisingplural additional light sources for illumination of the fiber-endsurface from plural additional angles different from the first andsecond illumination angles and different from one another.
 6. The fiberend-surface detection device according to claim 1, further comprising acontroller for alternately illuminating said first light source and saidsecond light source, and for operating said vision device to take imagesof the fiber end-surface under said alternate illuminations. 7.(canceled)
 8. The fiber end-surface detection device according to claim1, wherein said first light source supplies light to a reflectivesurface, said reflective surface oriented to the fiber end-surface at afirst angle of reflection and wherein said second light source supplieslight to the reflective surface, with said reflective surface orientedto the fiber end-surface at a second angle of reflection.
 9. A methodfor inspection the end-surface of an optical fiber, comprising:providing a first light source and a second light source, so that saidfirst and second light sources are located on opposite sides withrespect to a vision device position; and observing the fiber end-surfaceunder illumination from the first source and under illumination from thesecond source.
 10. The method according to claim 9, wherein said firstand second light sources comprise LEDs.
 11. The method according toclaim 10, wherein said first light source comprises a first LEDpositioned to illuminate the fiber end-surface from a first illuminationangle, and said second light source comprises a second LED positioned toilluminate the fiber end-surface from a second illumination angle andwherein said first and second illuminations angles are located onopposite sides with respect to the vision device position. 12.(canceled)
 13. The method according to claim 11, further comprisingproviding plural additional light sources for illumination of thefiber-end surface from plural additional angles different from the firstand second illumination angles and different from one another.
 14. Themethod according to claim 9, further comprising alternately illuminatingsaid first light source and said second light source, and observingimages of the fiber end-surface under said alternate illuminations. 15.The method according to claim 9, further comprising providing first andsecond prisms adapted to reflect light from said first and second lightsources toward the fiber end-surface, and to pass reflected light fromthe fiber end-surface for observing.
 16. The method according to claim9, wherein said providing a first light source comprises supplying lightto a reflective surface, said reflective surface oriented to the opticalfiber end-surface at a first angle of reflection and wherein saidproviding a second light source comprises supplying light to thereflective surface, with said reflective surface oriented to the opticalfiber end-surface at a second angle of reflection.
 17. The methodaccording to claim 9, further comprising superimposing observed imagesof the end-surface of the optical fiber to provide a combined image ofmultiple observed images.
 18. A fiber end-surface detection device,comprising: a processor; a first light source for illuminating the fiberend surface at a first illumination angle; a second light source forilluminating the fiber end surface at a second illumination angle; and avision device for observing the fiber end-surface under illuminationfrom the first light source and under illumination from the second lightsource, wherein said first and second light sources are located onopposite sides with respect to the vision device position and whereinsaid processor alternately illuminates said first light source andobtains a first image of the fiber end-surface from said vision device,and illuminates said second light source and obtains a second image ofthe fiber end-surface.
 19. The fiber end-surface detection deviceaccording to claim 18, wherein said first light source comprises a firstLED positioned to illuminate the fiber end-surface from the firstillumination angle, and said second source comprises a second LEDpositioned to illuminate the fiber end-surface from the secondillumination angle and wherein said first and second illuminationsangles are located on opposite sides with respect to the vision deviceposition.
 20. The fiber end-surface detection device according to claim18, wherein said first light source and second light source comprise avariable angle reflective surface receiving illumination light, saidfirst light source comprising said reflective surface positioned at afirst angle relative to the fiber end surface and said second lightsource comprising said reflective surface positioned at a second anglerelative to the fiber end surface.